[Objectives]  To provide a useful reference for the rational use of Light-Emitting Diode (LED) insect lamp traps for pest control in open vegetable fields. [Methods]  The species and quantity of insects trapped by twelve different narrow-spectrum LED lamp-traps and the trapping dynamics of insects captured, were recorded and compared. A commercially available long wave ultraviolet (UV) LED insect-trapping lamp was used as a control. [Results]  Nine phototactic insect pests (Stenochironomus nelumbus, Hymenia recurvalis, Spodoptera litura, Ricania speculum, Nezara viridula, Creatonotus gangis, Gryllotalpa orientalis, Leptocorisa sp. and Bactrocera cucurbitae), three natural enemy insects (Propylaea japonica, Harpalus sinicus and Sirthenea flavipes) and four neutral insects (Altica birmanensis, Sternolophus rufipes, Paederus sp. and Uloma sp.), were collected. S. nelumbus, H. recurvalis and A. birmanensis were the dominant species caught in lamp-traps. B. cucurbitae, Leptocorisa sp. and S. flavipes were rarely captured; all other species were common. Traps could be ranked in terms of the number of insects caught as follows; 440-445 nm > 460-470 nm > 390-400 nm > 410-420 nm > 380-390 nm > 450-460 nm. [Conclusion]  The optimum wavelength of lamp trap depends on the trapping dynamics of the targeted insect species. Timely and proper application of lamps with wavelengths of 390-400, 410-420, 440-445 and 450-460 nm can both effectively control the main insect pests, and reduce the bycatch of their natural enemies, in vegetable fields. These results provide a reference for pest forecasting and the physical control of insect pests, and also lay a foundation for standardizing the use of lamp traps and developing more efficient and intelligent LED lamp traps.